Safety helmet



FIG. 1 is the perspective view of a safety helmet showing my new design;

FIG. 2 is the front view thereof;

FIG. 3 is the rear view thereof;

FIG. 4 is the left side view thereof;

FIG. 5 is the right side view thereof;

FIG. 6 is the top view thereof; and,

FIG. 7 is the bottom view thereof. 

The ornamental design for a safety helmet, as shown and described. 